Heat sink



FIG. 1 is the perspective view of the top, front and left side of a heat sink showing our new design;

FIG. 2 is the front elevational view thereof;

FIG. 3 is the left elevational view thereof;

FIG. 4 is the top plan view thereof;

FIG. 5 is the bottom plan view thereof;

FIG. 6 is the section view of FIG. 4 along the line VI—VI thereof; and,

FIG. 7 is the section view of FIG. 4 along the line VII—VII.

The right elevational view is the same as the left elevational view.

The back elevational view is the same as the front elevational view. 

The ornamental design for a heat sink, as shown and described. 